speed up has_parens() (take 2) (#3052)

fixes #3050

test/mocha/parentheses.js

@@ -0,0 +1,105 @@
+var assert = require("assert");
+var uglify = require("../../");
+
+describe("parentheses", function() {
+    it("Should add trailing parentheses for new expressions with zero arguments in beautify mode", function() {
+        var tests = [
+            "new x(1);",
+            "new x;",
+            "new new x;",
+            "new (function(foo){this.foo=foo;})(1);",
+            "new (function(foo){this.foo=foo;})();",
+            "new (function test(foo){this.foo=foo;})(1);",
+            "new (function test(foo){this.foo=foo;})();",
+            "new true;",
+            "new (0);",
+            "new (!0);",
+            "new (bar = function(foo) {this.foo=foo;})(123);",
+            "new (bar = function(foo) {this.foo=foo;})();"
+        ];
+        var expected = [
+            "new x(1);",
+            "new x();",
+            "new new x()();",
+            "new function(foo) {\n    this.foo = foo;\n}(1);",
+            "new function(foo) {\n    this.foo = foo;\n}();",
+            "new function test(foo) {\n    this.foo = foo;\n}(1);",
+            "new function test(foo) {\n    this.foo = foo;\n}();",
+            "new true();",
+            "new 0();",
+            "new (!0)();",
+            "new (bar = function(foo) {\n    this.foo = foo;\n})(123);",
+            "new (bar = function(foo) {\n    this.foo = foo;\n})();"
+        ];
+        for (var i = 0; i < tests.length; i++) {
+            assert.strictEqual(
+                uglify.minify(tests[i], {
+                    output: {beautify: true},
+                    compress: false,
+                    mangle: false
+                }).code,
+                expected[i]
+            );
+        }
+    });
+
+    it("Should not add trailing parentheses for new expressions with zero arguments in non-beautify mode", function() {
+        var tests = [
+            "new x(1);",
+            "new x;",
+            "new new x;",
+            "new (function(foo){this.foo=foo;})(1);",
+            "new (function(foo){this.foo=foo;})();",
+            "new (function test(foo){this.foo=foo;})(1);",
+            "new (function test(foo){this.foo=foo;})();",
+            "new true;",
+            "new (0);",
+            "new (!0);",
+            "new (bar = function(foo) {this.foo=foo;})(123);",
+            "new (bar = function(foo) {this.foo=foo;})();"
+        ];
+        var expected = [
+            "new x(1);",
+            "new x;",
+            "new(new x);",
+            "new function(foo){this.foo=foo}(1);",
+            "new function(foo){this.foo=foo};",
+            "new function test(foo){this.foo=foo}(1);",
+            "new function test(foo){this.foo=foo};",
+            "new true;",
+            "new 0;",
+            "new(!0);",
+            "new(bar=function(foo){this.foo=foo})(123);",
+            "new(bar=function(foo){this.foo=foo});"
+        ];
+        for (var i = 0; i < tests.length; i++) {
+            assert.strictEqual(
+                uglify.minify(tests[i], {
+                    output: {beautify: false},
+                    compress: false,
+                    mangle: false
+                }).code,
+                expected[i]
+            );
+        }
+    });
+
+    it("Should compress leading parenthesis with reasonable performance", function() {
+        this.timeout(30000);
+        var code = [
+            "({}?0:1)&&x();",
+            "(function(){}).name;",
+        ];
+        for (var i = 16; --i >= 0;) {
+            [].push.apply(code, code);
+        }
+        code = code.join("");
+        var result = uglify.minify(code, {
+            compress: false,
+            mangle: false,
+        });
+        if (result.error) throw result.error;
+        // Dismal performance for `assert.strictEqual()` in Node.js 6
+        assert.ok(result.code === code);
+    });
+});